Did you get the sensor from the dealer or parts store? For whatever reason, they don't play well with the aftermarket parts. Had a similar experience with a 2005 Magnum R/T, put in aftermarket sensor, light stayed on, got one from the dealer and the problem was solved. Dealer was even a couple bucks cheaper too, shocked the hell out of me. I put a mechanical gauge on mine and had 30 or 35 psi idling warm.